Centrifugal filters or separators have been known for some time but have not been without problems in the cost of manufacture, ease of assembly and use on the automobile engine or any type of engines where such filters are typically found. Often these separators include clamping mechanisms which are spring-loaded to the extent that tools are usually required in removing those portions of the housing to permit access to the internal operating portions of the separator. In addition, threaded rods and nuts are usually included to secure the shafts and other portions of the rotary unit to the remainder of the housing on or adjacent to the engine. This has made those separators relatively expensive to manufacture because of the complexity of the parts involved and difficult to operate because of the nature of the attachment mechanisms particularly.
Not only the construction and assembly, but also, the mode of operation of these separators has been deficient in several areas. Proper flow paths may not always be established to ensure that the particles within the fluid being treated are thrown toward the peripheral portions of the rotary unit. In addition, the centrifugal force imparted to the fluid as it leaves the rotary unit often causes the fluid to swirl as it is delivered from the separator to the engine. The swirl remaining with the oil as it is dispensed from the separator reduces the effectiveness of the oil, because the desired flow pattern is not always achieved.
The invention includes several features which overcome the problems which have characterized the prior art in construction, mode of operation, and result. As explained above, a feature of the invention relates to a construction which improves the assembly procedures and reduces cost to the extent that the unit is rendered disposable. For example, the rotary unit includes a rigid, inlet shaft which is resiliently-fixed within the filter housing. A biasing mechanism or adapter is located adjacent the bottom of the housing for engagement with the bottom portion of the rigid shaft. In this way, the rotary unit with the rigid shaft in place is pressed against the biasing mechanism when the top of the housing is in place such that the shaft is biased against the top of the housing in a manner which secures the rotary unit in the correct position even during rotation at high speeds. By using such a construction, the threaded rods, nuts and external, spring-operated clamping mechanisms can be eliminated without loss in efficiency of the unit.
To achieve the desired flow pattern within the rotary unit, an upper baffle plate is located beneath the liquid inlet and this baffle plate, typically, extends from a hollow sleeve mounted on a non-rotating hollow shaft about which the centrifugal unit rotates. In this manner, as the fluid is forced under pressure through the inlet tube and the surrounding hollow shaft, the fluid is directed toward the peripheral elements of the rotary unit by the upper baffle plate before being directed to the bottom portion of the rotary unit for explusion. The rotary unit also has a lower baffle member extending from the interior, peripheral surface of the rotary unit towards its central portion. The latter baffle terminates to leave an open area near the central tube of the rotary unit for the cleaner fluid, but not the separated contaminants, to pass to outlet jets near the bottom of the rotary unit.
Baffled outlet means including vanes are located in the bottom portion of the housing beneath the jets of the rotary unit and above the outlet of the housing. Thus, the liquid leaving the rotary unit is subjected to stabilizing effect of the vanes prior to being dispensed through the outlet of the separator. This ensures that the fluid has the desired flow characteristics before being delivered to the engine. Such baffled outlet means may comprise a plurality of stationary vanes or may be in one piece.
In addition to all of the features which characterize the construction and operation of the separator, the attachment feature is one which adds to the simplicity of operation of this device. The top member forming the top of the housing is of the spin-on type which has a threaded internal surface allowing the entire separator to be spun on to a complementary connection on or adjacent the engine. Thus, once the separator has been used and requires replacement, it can be simply spun out of its connection and disposed of. Furthermore, as can be seen from the above discussion, not only is the centrifugal separator of the invention economical, but its efficiency is enhanced by the maintenance of the desired flow pattern of the baffle means as well as the straightening of the centrifugal motion of the fluid by the stationary radial vanes or baffle means, as the fluid leaves the housing. These features as well as others will be better appreciated in the following detailed discussion of the preferred embodiments.